Ernst Gunther, Duke of Schleswig-Holstein (August 11, 1863 – February 22, 1921) was a son of Frederick VIII, Duke of Schleswig-Holstein and Princess Adelheid of Hohenlohe-Langenburg. He inherited his father's title as titular duke of Schleswig-Holstein.
On August 2, 1898 in Coburg, he married Princess Dorothea of Saxe-Coburg and Gotha, daughter of Prince Philipp of Saxe-Coburg and Gotha and Princess Louise of Belgium. The grandfather of the bride, King Leopold II, did not attend the wedding but sent the Grand Cordon of the Order of Leopold as wedding gift.
The couple had no children. However, on 11 November 1920, Ernst Gunther adopted Prince Johann Georg and his sister Princess Marie Luise, children of Prince Albrecht of Schleswig-Holstein-Sonderburg-Glücksburg. Bavaria - Knight, Order of St. Hubert - February 1901
Belgium - Grand Cordon in the Order of Leopold - 1898.
Knight Grand Cross in the Order of the Crown.